pub trait ToSql<A, DB: Backend>: Debug {
// Required method
fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, DB>) -> Result;
}
Expand description
Serializes a single value to be sent to the database.
The output is sent as a bind parameter, and the data must be written in the expected format for the given backend.
When possible, implementations of this trait should prefer using an existing
implementation, rather than writing to out
directly. (For example, if you
are implementing this for an enum, which is represented as an integer in the
database, you should use i32::to_sql(x, out)
instead of writing to out
yourself.)
Any types which implement this trait should also
#[derive(AsExpression)]
.
Backend specific details
- For PostgreSQL, the bytes will be sent using the binary protocol, not text.
- For SQLite, all implementations should be written in terms of an existing
ToSql
implementation. - For MySQL, the expected bytes will depend on the return value of
type_metadata
for the given SQL type. SeeMysqlType
for details. - For third party backends, consult that backend’s documentation.
Examples
Most implementations of this trait will be defined in terms of an existing implementation.
#[repr(i32)]
#[derive(Debug, Clone, Copy, AsExpression)]
#[diesel(sql_type = Integer)]
pub enum MyEnum {
A = 1,
B = 2,
}
impl<DB> ToSql<Integer, DB> for MyEnum
where
DB: Backend,
i32: ToSql<Integer, DB>,
{
fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, DB>) -> serialize::Result {
match self {
MyEnum::A => 1.to_sql(out),
MyEnum::B => 2.to_sql(out),
}
}
}
Using temporary values as part of the ToSql
implementation requires additional
work.
Backends using RawBytesBindCollector
as BindCollector
copy the serialized values as part
of Write
implementation. This includes the Mysql
and the Pg
backend provided by diesel.
This means existing ToSql
implementations can be used even with
temporary values. For these it is required to call
Output::reborrow
to shorten the lifetime of the Output
type correspondingly.
#[repr(i32)]
#[derive(Debug, Clone, Copy, AsExpression)]
#[diesel(sql_type = Integer)]
pub enum MyEnum {
A = 1,
B = 2,
}
impl ToSql<Integer, diesel::pg::Pg> for MyEnum
where
i32: ToSql<Integer, diesel::pg::Pg>,
{
fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, diesel::pg::Pg>) -> serialize::Result {
let v = *self as i32;
<i32 as ToSql<Integer, diesel::pg::Pg>>::to_sql(&v, &mut out.reborrow())
}
}
For any other backend the Output::set_value
method provides a way to
set the output value directly. Checkout the documentation of the corresponding
BindCollector::Buffer
type for provided From<T>
implementations for a list
of accepted types. For the Sqlite
backend see SqliteBindValue
.
#[repr(i32)]
#[derive(Debug, Clone, Copy, AsExpression)]
#[diesel(sql_type = Integer)]
pub enum MyEnum {
A = 1,
B = 2,
}
impl ToSql<Integer, diesel::sqlite::Sqlite> for MyEnum
where
i32: ToSql<Integer, diesel::sqlite::Sqlite>,
{
fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, diesel::sqlite::Sqlite>) -> serialize::Result {
out.set_value(*self as i32);
Ok(IsNull::No)
}
}
Required Methods§
Implementations on Foreign Types§
source§impl<'a, T, ST, DB> ToSql<ST, DB> for Cow<'a, T>where
T: 'a + ToOwned + ToSql<ST, DB> + ?Sized,
DB: Backend,
Self: Debug,
impl<'a, T, ST, DB> ToSql<ST, DB> for Cow<'a, T>where T: 'a + ToOwned + ToSql<ST, DB> + ?Sized, DB: Backend, Self: Debug,
source§impl<DB> ToSql<Binary, DB> for [u8]where
for<'a> DB: Backend<BindCollector<'a> = RawBytesBindCollector<DB>>,
impl<DB> ToSql<Binary, DB> for [u8]where for<'a> DB: Backend<BindCollector<'a> = RawBytesBindCollector<DB>>,
source§impl<DB> ToSql<Text, DB> for strwhere
for<'a> DB: Backend<BindCollector<'a> = RawBytesBindCollector<DB>>,
impl<DB> ToSql<Text, DB> for strwhere for<'a> DB: Backend<BindCollector<'a> = RawBytesBindCollector<DB>>,
source§impl<ST, T> ToSql<Array<ST>, Pg> for [T]where
Pg: HasSqlType<ST>,
T: ToSql<ST, Pg>,
Available on crate feature postgres_backend
only.
impl<ST, T> ToSql<Array<ST>, Pg> for [T]where Pg: HasSqlType<ST>, T: ToSql<ST, Pg>,
postgres_backend
only.source§impl<ST, T> ToSql<Array<ST>, Pg> for Vec<T>where
ST: 'static,
[T]: ToSql<Array<ST>, Pg>,
T: Debug,
Available on crate feature postgres_backend
only.
impl<ST, T> ToSql<Array<ST>, Pg> for Vec<T>where ST: 'static, [T]: ToSql<Array<ST>, Pg>, T: Debug,
postgres_backend
only.source§impl<ST, T> ToSql<Nullable<Array<ST>>, Pg> for [T]where
[T]: ToSql<Array<ST>, Pg>,
ST: 'static,
Available on crate feature postgres_backend
only.
impl<ST, T> ToSql<Nullable<Array<ST>>, Pg> for [T]where [T]: ToSql<Array<ST>, Pg>, ST: 'static,
postgres_backend
only.source§impl<ST, T> ToSql<Nullable<Array<ST>>, Pg> for Vec<T>where
ST: 'static,
Vec<T>: ToSql<Array<ST>, Pg>,
Available on crate feature postgres_backend
only.
impl<ST, T> ToSql<Nullable<Array<ST>>, Pg> for Vec<T>where ST: 'static, Vec<T>: ToSql<Array<ST>, Pg>,
postgres_backend
only.source§impl<ST, T> ToSql<Nullable<Range<ST>>, Pg> for (Bound<T>, Bound<T>)where
ST: 'static,
(Bound<T>, Bound<T>): ToSql<Range<ST>, Pg>,
Available on crate feature postgres_backend
only.
impl<ST, T> ToSql<Nullable<Range<ST>>, Pg> for (Bound<T>, Bound<T>)where ST: 'static, (Bound<T>, Bound<T>): ToSql<Range<ST>, Pg>,
postgres_backend
only.source§impl<ST, T> ToSql<Range<ST>, Pg> for (Bound<T>, Bound<T>)where
T: ToSql<ST, Pg>,
Available on crate feature postgres_backend
only.
impl<ST, T> ToSql<Range<ST>, Pg> for (Bound<T>, Bound<T>)where T: ToSql<ST, Pg>,
postgres_backend
only.source§impl<T, ST, DB> ToSql<Nullable<ST>, DB> for Option<T>where
T: ToSql<ST, DB>,
DB: Backend,
ST: SqlType<IsNull = NotNull>,
impl<T, ST, DB> ToSql<Nullable<ST>, DB> for Option<T>where T: ToSql<ST, DB>, DB: Backend, ST: SqlType<IsNull = NotNull>,
source§impl<__DB> ToSql<Nullable<BigInt>, __DB> for i64where
__DB: Backend,
Self: ToSql<BigInt, __DB>,
impl<__DB> ToSql<Nullable<BigInt>, __DB> for i64where __DB: Backend, Self: ToSql<BigInt, __DB>,
source§impl<__DB> ToSql<Nullable<Binary>, __DB> for Vec<u8>where
__DB: Backend,
Self: ToSql<Binary, __DB>,
impl<__DB> ToSql<Nullable<Binary>, __DB> for Vec<u8>where __DB: Backend, Self: ToSql<Binary, __DB>,
source§impl<__DB> ToSql<Nullable<Binary>, __DB> for [u8]where
__DB: Backend,
Self: ToSql<Binary, __DB>,
impl<__DB> ToSql<Nullable<Binary>, __DB> for [u8]where __DB: Backend, Self: ToSql<Binary, __DB>,
source§impl<__DB> ToSql<Nullable<Double>, __DB> for f64where
__DB: Backend,
Self: ToSql<Double, __DB>,
impl<__DB> ToSql<Nullable<Double>, __DB> for f64where __DB: Backend, Self: ToSql<Double, __DB>,
source§impl<__DB> ToSql<Nullable<Float>, __DB> for f32where
__DB: Backend,
Self: ToSql<Float, __DB>,
impl<__DB> ToSql<Nullable<Float>, __DB> for f32where __DB: Backend, Self: ToSql<Float, __DB>,
source§impl<__DB> ToSql<Nullable<Integer>, __DB> for i32where
__DB: Backend,
Self: ToSql<Integer, __DB>,
impl<__DB> ToSql<Nullable<Integer>, __DB> for i32where __DB: Backend, Self: ToSql<Integer, __DB>,
source§impl<__DB> ToSql<Nullable<MacAddr>, __DB> for [u8; 6]where
__DB: Backend,
Self: ToSql<MacAddr, __DB>,
Available on crate feature postgres_backend
only.
impl<__DB> ToSql<Nullable<MacAddr>, __DB> for [u8; 6]where __DB: Backend, Self: ToSql<MacAddr, __DB>,
postgres_backend
only.source§impl<__DB> ToSql<Nullable<SmallInt>, __DB> for i16where
__DB: Backend,
Self: ToSql<SmallInt, __DB>,
impl<__DB> ToSql<Nullable<SmallInt>, __DB> for i16where __DB: Backend, Self: ToSql<SmallInt, __DB>,
source§impl<__DB> ToSql<Nullable<Text>, __DB> for Stringwhere
__DB: Backend,
Self: ToSql<Text, __DB>,
impl<__DB> ToSql<Nullable<Text>, __DB> for Stringwhere __DB: Backend, Self: ToSql<Text, __DB>,
source§impl<__DB> ToSql<Nullable<Timestamp>, __DB> for SystemTimewhere
__DB: Backend,
Self: ToSql<Timestamp, __DB>,
impl<__DB> ToSql<Nullable<Timestamp>, __DB> for SystemTimewhere __DB: Backend, Self: ToSql<Timestamp, __DB>,
Implementors§
impl ToSql<Date, Pg> for PgDate
postgres_backend
only.impl ToSql<Interval, Pg> for PgInterval
postgres_backend
only.impl ToSql<Money, Pg> for PgMoney
postgres_backend
only.impl ToSql<Numeric, Pg> for PgNumeric
postgres_backend
only.impl ToSql<Time, Pg> for PgTime
postgres_backend
only.impl ToSql<Timestamp, Pg> for PgTimestamp
postgres_backend
only.impl ToSql<Timestamptz, Pg> for PgTimestamp
postgres_backend
only.impl<'a, DB> ToSql<Text, DB> for MigrationVersion<'a>where Cow<'a, str>: ToSql<Text, DB>, DB: Backend,
impl<'a, __DB> ToSql<Nullable<Text>, __DB> for MigrationVersion<'a>where __DB: Backend, Self: ToSql<Text, __DB>,
impl<__DB> ToSql<Nullable<Date>, __DB> for PgDatewhere __DB: Backend, Self: ToSql<Date, __DB>,
postgres_backend
only.impl<__DB> ToSql<Nullable<Interval>, __DB> for PgIntervalwhere __DB: Backend, Self: ToSql<Interval, __DB>,
postgres_backend
only.impl<__DB> ToSql<Nullable<Money>, __DB> for PgMoneywhere __DB: Backend, Self: ToSql<Money, __DB>,
postgres_backend
only.impl<__DB> ToSql<Nullable<Numeric>, __DB> for PgNumericwhere __DB: Backend, Self: ToSql<Numeric, __DB>,
postgres_backend
only.impl<__DB> ToSql<Nullable<Time>, __DB> for PgTimewhere __DB: Backend, Self: ToSql<Time, __DB>,
postgres_backend
only.impl<__DB> ToSql<Nullable<Timestamp>, __DB> for PgTimestampwhere __DB: Backend, Self: ToSql<Timestamp, __DB>,
postgres_backend
only.impl<__DB> ToSql<Nullable<Timestamptz>, __DB> for PgTimestampwhere __DB: Backend, Self: ToSql<Timestamptz, __DB>,
postgres_backend
only.